Multi-criteria decision analysis framework for engaging stakeholders in river pollution risk management.

Water pollution presents a substantial environmental challenge with extensive implications for water resources, ecosystem sustainability, and human health. Using a South African catchment, this study aimed to provide watershed managers with a framework for selecting best management practices (BMPs) to reduce pollution and the related risk to river users, while also including the perspectives of key catchment stakeholders. The framework encompassed the identification of and consultation with key stakeholders within the catchment. A Multi-Criteria Decision Analysis (MCDA) methodology using the Simple Multi-Attribute Rating Technique for Enhanced Stakeholder Take-up (SMARTEST) was used to identify and prioritise suitable BMPs in a case study. Decision alternatives and assessment criteria as well as their weights were derived based on stakeholder responses to a two-stage survey. Stakeholders included those utilising the river for domestic and recreational purposes, municipal representatives, scientists, NGOs, and engineers. The assessment of decision alternatives considered environmental, economic, and social criteria. The aggregated scores for decision alternatives highlighted the significance of involving stakeholders throughout the decision process. This study recommends the pairing of structural and non-structural BMPs. The findings provide valuable insights for catchment managers, policymakers, and environmental stakeholders seeking inclusive and effective pollution mitigation strategies in a catchment.

Quantitative assessment of human health risks from chemical pollution in the uMsunduzi River, South Africa.

A quantitative chemical risk assessment was performed using published data as well as data from the official monitoring programme for the uMsunduzi River in KwaZulu-Natal, South Africa. The chemicals assessed were organochlorinated pesticides (OCPs), pharmaceuticals and personal care products (PPCPs), heavy metals, and nitrates and phosphates. The water from uMsunduzi River is used locally without treatment. Consequently, the exposure routes investigated were via ingestion during domestic drinking and incidental ingestion during recreational activities, which were swimming and non-competitive canoeing, for both adults and children. For the individual chemicals, non-carcinogenic risks using the hazard quotient (HQ) and carcinogenic risks using the cancer risk (CR) were quantified. It was found that the exposed population is likely to experience non-carcinogenic effects from pesticides and phosphates, but not from PPCPs, heavy metals and nitrates. This study also found that the carcinogenic risks for OCPs were higher than the tolerable limit of 10-5, while for lead the risk was below the tolerable limit. Some of the activities that potentially contribute to chemicals onto the uMsunduzi River are subsistence farming, small plantations, illegal dumping, industries, and broken sewers. The findings of this study may act as the technical foundation for the introduction of pollution reduction measures within the catchment, including public education.

Improving knowledge, attitudes, and practices on dengue and diarrhea in rural primary school students, their parents, and teachers in Colombia: A cluster-randomized controlled trial.

BACKGROUND: Improved education on water-related diseases in schools could help to reduce disease burden. This paper presents specific results on knowledge, attitudes and practices (KAP) of a cluster-randomized controlled trial to reduce diarrheal disease and dengue entomological risk factors in rural primary schools in Colombia. The aim was to investigate whether enhanced educational interventions on dengue and diarrheal disease in schools could improve KAP scores related to these diseases in students and teachers in rural primary schools, as well as the students' parents. METHODOLOGY/PRINCIPAL FINDINGS: A factorial cluster-randomized controlled trial was carried out in 35 rural primary schools in two municipalities in Cundinamarca, central Colombia. Schools were randomized into four arms: interventions related to diarrheal disease (DIA), dengue (DEN), both (DIADEN), or no interventions (control, CON). Both educational and physical interventions to reduce risk factors of dengue and diarrhea were implemented. Comprehensive teachers' manuals were developed and deployed to guide the learning activities. The intervention was carried out over two school years. The knowledge scores of students receiving dengue interventions (DEN, DIADEN) increased by 1.16 point score (0.75-1.56, p<0.001) and those receiving diarrhea interventions (DIA, DIADEN) increased by 1.15 point score (0.67-1.63, p<0.001). The attitude and practice scores of students receiving the diarrhea interventions increased (Attitudes: 0.41 [0.11-0.71, p = 0.01]; Practices: 0.33 [0.01-0.65, p = 0.042]), but not for those receiving the dengue interventions (p = 0.31 and p = 0.08, respectively). CONCLUSIONS/SIGNIFICANCE: There were increases in knowledge scores among students, their teachers and their parents for both diseases. However, the attitudes and practices components were not affected to the same extent. The hypothesis that the students would disseminate knowledge acquired from the educational interventions to their parents was confirmed for dengue, but not for diarrhea. TRIAL REGISTRATION: ISRCTN40195031 The trial is registered in the Current Controlled Trials under Infections and Infestations category.

Water quality modelling and quantitative microbial risk assessment for uMsunduzi River in South Africa.

South African rivers generally receive waste from inadequate wastewater infrastructure, mines, and farming activities, among others. The uMsunduzi River in KwaZulu-Natal, South Africa, is among these recipients with recorded poor to very poor water quality. To identify parts of the uMsunduzi River that are polluted by Cryptosporidium and Escherichia coli (E. coli), this study mapped out pollutants emanating from point and non-point sources using the Soil and Water Assessment Tool (SWAT). Streamflow calibration in the upper and lower reaches of the catchment showed good performance with R2 of 0.64 and 0.58, respectively. SWAT water quality output data were combined with a Quantitative Microbial Risk Assessment (QMRA) to understand the microbial health implications for people using river water for drinking, recreational swimming, and non-competitive canoeing. QMRA results for Cryptosporidium and pathogenic E. coli showed that the probability of infection for most users exceeds the acceptable level for drinking and recreation as outlined in the South African water quality guidelines, and by the World Health Organization (WHO). The results of this study can be used as a baseline to assess the economic and health implications of different management plans, resulting in better-informed, cost-effective, and impactful decision-making.

An assessment of the health risks associated with shared sanitation: a case study of the community ablution blocks in Durban, South Africa.

Shared sanitation facilities have been hailed as an innovative approach to solve the challenge with sanitation access. However, these facilities may act as hotspots for disease transmission due to unhygienic conditions. In this study we used quantitative (based on Escherichia coli contamination) techniques to assess the health risks associated with the use of community ablution blocks (CABs). The most contaminated surfaces were the cistern handle (5.7 Log10 cfu/cm2) and internal pull latch (5.8 Log10 cfu/cm2). Based on the E. coli contamination, at least two people out of 100 CAB users might be potentially infected when they touch "hot" surfaces. These risks were modelled assuming transfer of potentially pathogenic E. coli from these surfaces to the mouth. The incorporation of risk-reduction measures, such as wiping of these surfaces or washing of hands, could potentially result in significant reduction of infection risks. The most significant risk-reduction intervention was determined to be wiping of the contact surfaces, especially twice prior to contact. A combination of risk-reduction interventions could further reduce the risks. This study shows that contamination of contact surfaces within shared CABs could lead to increased risks of infections, requiring measures aimed at reducing the associated risks. The risk assessment framework used in this study could therefore be applied in similar settings to estimate associated health risks with the use of such facilities.

Integrated disease management: arboviral infections and waterborne diarrhoea.

Water-related diseases such as diarrhoeal diseases from viral, bacterial and parasitic organisms and Aedes-borne arboviral diseases are major global health problems. We believe that these two disease groups share common risk factors, namely inadequate household water management, poor sanitation and solid waste management. Where water provision is inadequate, water storage is essential. Aedes mosquitoes commonly breed in household water storage containers, which can hold water contaminated with enteric disease-causing organisms. Microbiological contamination of water between source and point-of-use is a major cause of reduced drinking-water quality. Inadequate sanitation and solid waste management increase not only risk of water contamination, but also the availability of mosquito larval habitats. In this article we discuss integrated interventions that interrupt mosquito breeding while also providing sanitary environments and clean water. Specific interventions include improving storage container design, placement and maintenance and scaling up access to piped water. Vector control can be integrated into sanitation projects that target sewers and drains to avoid accumulation of stagnant water. Better management of garbage and solid waste can reduce the availability of mosquito habitats while improving human living conditions. Our proposed integration of disease interventions is consistent with strategies promoted in several global health frameworks, such as the sustainable development goals, the global vector control response, behavioural change, and water, sanitation and hygiene initiatives. Future research should address how interventions targeting water, sanitation, hygiene and community waste disposal also benefit Aedes-borne disease control. The projected effects of climate change mean that integrated management and control strategies will become increasingly important.

Diarrhées provoquées par la présence d'organismes viraux, bactériens et parasites, arboviroses véhiculées par les moustiques Aedes: les maladies liées à l'eau constituent un problème de santé majeur dans le monde. Nous pensons que ces deux groupes de maladies partagent les mêmes facteurs de risque, à savoir une mauvaise gestion de l'eau au sein du foyer ainsi qu'un manque d'assainissement et de traitement des déchets solides. Dans les endroits où l'approvisionnement en eau est insuffisant, les conditions de conservation sont essentielles. Les moustiques Aedes se reproduisent fréquemment dans les réservoirs d'eau à domicile, qui peuvent dès lors contenir de l'eau contaminée par des organismes responsables d'infections entériques. La contamination microbiologique de l'eau, entre la source et le moment où elle est consommée, représente l'une des causes principales d'altération de la qualité de l'eau potable. Le manque d'assainissement et de traitement des déchets solides fait augmenter le risque de contamination de l'eau, mais aussi le nombre de biotopes disponibles pour les larves de moustique. Dans cet article, nous parlons des interventions intégrées qui permettent d'interrompre la reproduction des moustiques tout en créant des environnements sanitaires adaptés et de l'eau propre. Ces interventions spécifiques prévoient notamment une optimisation de la conception, du placement et de l'entretien des réservoirs, ainsi qu'un meilleur accès à l'eau courante. La lutte contre les vecteurs peut être incorporée dans des projets d'assainissement qui ciblent les égouts et canalisations, afin d'éviter toute accumulation d'eau stagnante. Une meilleure gestion des ordures ménagères et des déchets solides peut réduire le nombre de biotopes disponibles pour les moustiques, mais aussi améliorer les conditions de vie de la population. Nous proposons une gestion intégrée des maladies cohérente avec les stratégies mises en avant dans plusieurs cadres de santé mondiaux tels que les objectifs de développement durable, l'action mondiale pour lutter contre les vecteurs, le changement de comportement ainsi que les initiatives relatives à l'approvisionnement en eau, l'assainissement et l'hygiène. Les futures recherches devraient étudier la façon dont les interventions dédiées à l'eau, à l'assainissement, à l'hygiène et à l'élimination des déchets au sein des communautés contribuent également à la lutte contre les maladies véhiculées par les moustiques Aedes. Compte tenu des effets attendus du changement climatique, les stratégies de lutte et de gestion intégrée vont gagner en importance.

Las enfermedades relacionadas con el agua, como las enfermedades diarreicas por organismos víricos, bacterianos y parasitarios, y las enfermedades arbovirales transmitidas por el Aedes, son importantes problemas sanitarios a nivel mundial. Creemos que estos dos grupos de enfermedades comparten factores de riesgo comunes, es decir, una gestión inadecuada del agua en los hogares, un saneamiento deficiente y la gestión de los residuos sólidos. Cuando el suministro de agua es inadecuado, el almacenamiento de agua es esencial. Los mosquitos Aedes suelen criar en los recipientes de almacenamiento de agua de los hogares, que pueden contener agua contaminada con organismos causantes de enfermedades entéricas. La contaminación microbiológica del agua entre la fuente y el punto de uso es una de las principales causas de la reducción de la calidad del agua potable. Un saneamiento y una gestión de residuos sólidos inadecuados no solo aumentan el riesgo de contaminación del agua, sino también la disponibilidad de hábitats para las larvas de mosquitos. En este artículo se analizan las intervenciones integradas que interrumpen la cría de mosquitos al tiempo que proporcionan entornos sanitarios y agua limpia. Las intervenciones específicas incluyen la mejora del diseño, la colocación y el mantenimiento de los contenedores de almacenamiento y la ampliación del acceso al agua corriente. El control de los vectores puede integrarse en proyectos de saneamiento dirigidos a las alcantarillas y los desagües para evitar la acumulación de agua estancada. Una mejor gestión de la basura y los residuos sólidos puede reducir la disponibilidad de hábitats para los mosquitos y mejorar las condiciones de vida de las personas. Nuestra propuesta de integración de las intervenciones contra la enfermedad es coherente con las estrategias promovidas en varios marcos sanitarios mundiales, como los objetivos de desarrollo sostenible, la respuesta mundial de control de vectores, el cambio de comportamiento y las iniciativas de agua, saneamiento e higiene. La investigación futura debería abordar cómo las intervenciones dirigidas al agua, el saneamiento, la higiene y la eliminación de residuos de la comunidad también benefician al control de las enfermedades transmitidas por el Aedes. Los efectos previstos del cambio climático significan que las estrategias de gestión y control integrados serán cada vez más importantes.

Identification, antibiotic resistance, and virulence profiling of Aeromonas and Pseudomonas species from wastewater and surface water.

Aquatic environments are hotspots for the spread of antibiotic-resistant bacteria and genes due to pollution caused mainly by anthropogenic activities. The aim of this study was to evaluate the impact of wastewater effluents, informal settlements, hospital, and veterinary clinic discharges on the occurrence, antibiotic resistance profile and virulence signatures of Aeromonas spp. and Pseudomonas spp. isolated from surface water and wastewater. High counts of Aeromonas spp. (2.5 (± 0.8) - 3.3 (± 0.4) log10 CFU mL-1) and Pseudomonas spp. (0.6 (± 1.0) - 1.8 (± 1.0) log10 CFU mL-1) were obtained. Polymerase chain reaction (PCR) and MALDI-TOF characterization identified four species of Aeromonas and five of Pseudomonas. The isolates displayed resistance to 3 or more antibiotics (71% of Aeromonas and 94% of Pseudomonas). Aeromonas spp. showed significant association with the antibiotic meropenem (χ2 = 3.993, P < 0.05). The virulence gene aer in Aeromonas was found to be positively associated with the antibiotic resistance gene blaOXA (χ2 = 6.657, P < 0.05) and the antibiotic ceftazidime (χ2 = 7.537, P < 0.05). Aeromonas recovered from both wastewater and surface water displayed high resistance to ampicillin and had higher multiple antibiotic resistance (MAR) indices close to the hospital. Pseudomonas isolates on the other hand exhibited low resistance to carbapenems but very high resistance to the third-generation cephalosporins and cefixime. The results showed that some of the Pseudomonas spp. and Aeromonas spp. isolates were extended-spectrum ß-lactamase producing bacteria. In conclusion, the strong association between virulence genes and antibiotic resistance in the isolates shows the potential health risk to communities through direct and indirect exposure to the water.

Impact of informal settlements and wastewater treatment plants on helminth egg contamination of urban rivers and risks associated with exposure.

The quality of surface water could be influenced by both anthropogenic and natural factors. This study was designed to determine the impact of informal settlement and wastewater treatment plants on helminth egg contamination of urban rivers and the risks associated with everyday use. We also ascertained the accumulation of these eggs in the river sediments. The study was carried out in two rivers in the eThekwini Municipality of South Africa. Grab samples were taken at different points over a 10-month period. Ascaris spp., hookworm, Toxocara spp., Trichuris spp. and Taenia spp. were the helminth eggs detected in both the water column and sediments, with mean Ascaris spp. eggs of 0-6.3 (± 5.1)/L in the water and 0-6.8 (± 5.2)/kg in sediment samples. The helminth egg concentrations showed seasonal variation, probably due to changes in infection levels of the populations or natural factors, such as rainfall. The informal settlements had a greater impact than treated wastewater. For every 10,000 recreational users of the rivers 19 to 58 may be infected under undisturbed conditions, increasing to 29-88 individuals when the riverbed is disturbed. The risk from agricultural use of the rivers was above the tolerable risk values applicable for wastewater reuse, recommended by the World Health Organization. This calls for a re-evaluation of the policies governing surface water quality assessment, where the inclusion of helminth eggs and sediment monitoring will be critical.

Impact of sludge bulking on receiving environment using quantitative microbial risk assessment (QMRA)-based management for full-scale wastewater treatment plants.

During sludge bulking in wastewater treatment plants (WWTPs), high amounts of potentially pathogenic bacteria would release into the environment, causing various human-health risks. This is the first study attempting to assess the microbial infections associated with the reuse of WWTP effluents under various bulking conditions. Three common waterborne pathogens, viz., E. coli O157:H7, Salmonella, and Mycobacterium, were quantified from full-scale WWTPs using DNA extraction and qPCR at different sludge volume indices (SVIs). The detected pathogens were incorporated into a quantitative microbial risk assessment (QMRA) model to determine the applicability of WWTP discharge for recreational (bathing) activities and agricultural practices. The QMRA exposures were children, women, and men during swimming, and farmers and vegetable consumers during irrigation. Bacterial abundance in the treated wastewater increased in response to SVIs, and the QMRA values at all bulking events exceeded the tolerable risk of one case of infection per 10,000 people per year. Hence, various disinfection scenarios (chlorination, ultraviolet, and ozonation) were hypothetically tested to control the risks associated with pathogenic bacteria, allowing for safe disposal and reuse of the treated effluent. The ultraviolet application provided the highest ability to inactivate the pathogenic bacteria, except for the case of children exposed to Salmonella infection during swimming. The reduction of Mycobacterium infection risks with either chlorination or ozonation showed inefficient results. This study would be helpful for the management of human health risks associated with effluent wastewater containing pathogens, i.e., particularly concerning the case of sludge bulking.

Antibiogram and beta-lactamase genes among cefotaxime resistant E. coli from wastewater treatment plant.

BACKGROUND: The World Health Organization (WHO) recently classified Enterobacteriaceae resistance to third-generation cephalosporin into the group of pathogens with critical criteria for future research. METHODS: A study to assess the antibiogram and beta-lactamase genes among the cefotaxime resistant E. coli (CREc) from a South African wastewater treatment plant (WWTP) was conducted using standard phenotypic and molecular biology characterization methods. RESULTS: Approximate total E. coli (TEc) concentration (log10 CFU/mL) ranged between 5.7 and 6.8 among which cefotaxime resistant E. coli were between 1.8 and 4.8 (log10 CFU/mL) for cefotaxime antibiotic concentration of 4 and 8 mg/L in the influent samples. Effluent samples, heavily influenced by the chlorination had only 0.3 log10 CFU/mL of TEc. Fifty-one cefotaxime resistant isolates were selected out of an overall of 75 isolates, and subjected to a new round of testing, with a follow up of 36 and 48 isolates for both colistin and gentamicin, respectively as guided by initial results. Selected CREc exhibited resistance to amoxicillin-clavulanic acid (35.3%; n = 51), colistin sulphate (76.5%; n = 36), ciprofloxacin (47.1%; n = 51), gentamicin (87.5%; n = 48) and intermediate-resistance to meropenem (11.8%; n = 51). Extended spectrum-beta-lactamase genes detected, viz.: blaCTX-M (52.6%; n = 38) and blaTEM (84.2%; n = 38) and concurrent blaCTX-M + blaTEM (36.8%; n = 38), but no blaSHV was detected. Carbapenem resistance genes, blaKPC-2 (15.8%; n = 38), blaOXA-1 (57.9%; n = 38), blaNDM-1 (15.8%; n = 38) were also detected. Approximately, 10.5 - 36.8% (n = 38) co-occurrence of two or more beta-lactamase genes was detected in some isolates. Out of the selected number (n = 30), 7(23.3%) were enterotoxigenic E. coli (ETEC), 14 (46.7%) were Enteroaggregative E. coli (EAEC), but no enteropathogenic E. coli (EPEC) was detected. CONCLUSION: Resistance to cefotaxime and the presence of a wide range of beta-lactamase genes exposed the potential risks associated with these pathogens via occupational and domestic exposure during the reuse of treated wastewater.

Reasons for absenteeism in rural primary schools in two Colombian municipalities / Razones de ausentismo en escuelas primarias rurales de dos municipios colombianos / Razões do não comparecimento nas escolas primarias rurais nos municípios colombianos

Background: School absenteeism is a considerable problem generally related to higher dropout rates, poor academic achievement and school lag. This study determined the frequency and causes of overall and illness-related absenteeism of students in rural schools from two Colombian municipalities. Methods: A prospective and descriptive study was conducted in a population of 948 school children from 34 rural schools. Absenteeism data were collected for 2013 academic year consisted of the number of students registered and absent by grade, school, day and reason for absence. Absence rates (overall and illness-related absenteeism) were recorded, based on full or partial days absence, measured both as episodes, and accumulating the number of days. Results: From the students included in the study, 55.1% were male and 71.6% were between 5 and 9 years old. The overall absence rate was 5.7 episodes per child-year (95% confidence interval 5.5 to 5.8) and 8.6 days per child-year (8.4 to 8.9). The main reasons for non-attendance were illness (24.4%), medical or dental check-up (12.9%), travel (12.3%), lack of motivation to attend school (10.0%) and bad weather (9.3%). The illness- related absence rate was 1.4 episodes per child-year (95% confidence interval 1.3 to 1.5) and 2.5 days per child-year (2.4 to 2.6). The main reasons for illness-related absence were cold (37.0%), nonspecific fever (10.9%) and stomach pain or vomiting (8.4%). Conclusions: In this study, the most common reasons for non-attendance were illness-related. The importance of respiratory and gastrointestinal infections in absenteeism was evident, showing rates similar to other urban school studies. Then, the results of this study provide knowledge on the magnitude and reasons for absenteeism in rural schoolchildren.

Antecedentes. El ausentismo escolar es un problema importante relacionado con altas tasas de abandono escolar, bajo rendimiento académico y rezago escolar. Este estudio determinó la frecuencia y las causas del ausentismo general y el ausentismo relacionado con la enfermedad en estudiantes de escuelas rurales de dos municipios de Colombia. Métodos. Se realizó un estudio descriptivo en una población de 948 escolares de 34 escuelas rurales. Los datos de ausentismo recopilados para el año 2013 consistieron en el número de episodios y días de ausentismo por grado y motivo de ausencia general y por enfermedad. Se calcularon las tasas de ausentismo general y por enfermedad. Resultados. El 55,1% de la población participante eran hombres y el 71,6% tenían entre 5 y 9 años. La tasa de ausentismo general fue 5,7 episodios por niño-año, IC 95% (5,5-5,8) y 8,6 días por niño-año, IC 95% (8,4-8,9). Las principales razones del ausentismo fueron enfermedades (24,4%), chequeo médico u odontológico (12,9%), viajes (12,3%), falta de motivación para asistir a la escuela (10,0%) y mal clima (9,3%). La tasa de ausentismo por enfermedad fue 1,4 episodios por niño-año IC 95% (1,3-1,5) y 2,5 días por niño-año IC 95% (2,4-2,6). Las principales razones del ausentismo por enfermedad fueron el resfriado común (37,0%), la fiebre inespecífica (10,9%) y el dolor de estómago o vómito (8,4%). Conclusiones. Las razones más comunes para la no asistencia estuvieron relacionadas con la enfermedad. La importancia de las infecciones respiratorias y gastrointestinales en el absentismo fue evidente, mostrando tasas similares a las de otros estudios en escuelas urbanas. Los resultados de este estudio proporcionan conocimiento sobre la magnitud y las razones del absentismo en la población escolar rural.

Antecedentes. O absentismo escolar é um grande problema relacionado às altas taxas de evasão escolar, baixo desempenho acadêmico e atraso escolar. Este estudo determinou a frequência e causas do não comparecimento geral e por doenças em estudantes de escolas rurais de dois municípios da Colômbia. Métodos. Estudo descritivo, realizado em uma população de 948 escolares de 34 escolas rurais. Os dados de absentismo coletados para 2013 consistiram no número de episódios e dias de não comparecimento por grau e motivo da ausência geral e por doença, foram calculadas as taxas de cada evento. Resultados. 55,1% da população participante eram crianças masculinas do primeiro grau, 71,6% entre 5 e 9 anos de idade. A taxa geral de absentismo foi de 5,7 episódios por criança-ano, IC95% (5,5-5,8) e 8,6 dias por criança-ano, IC95% (8,4-8,9). Os principais motivos do não comparecimento foram doenças (24,4%), check-up médico ou odontológico (12,9%), viagens (12,3%), falta de motivação para frequentar a escola (10,0%) e mau tempo (9,3%). A taxa de absentismo da doença foi de 1,4 episódios por IC95% criança-ano (1,3-1,5) e 2,5 dias por IC95% criança-ano (2,4-2,6). Os principais motivos da ausência de doença foram resfriado comum (37,0%), febre inespecífica (10,9%) e dor de estômago ou vômito (8,4%). Conclusões. Os motivos mais comuns de não comparecimento foram relacionados à doença. A importância das infecções respiratórias e gastrointestinais no absenteísmo foi evidente, mostrando taxas semelhantes às de outros estudos em escolas urbanas. Os resultados deste estudo fornecem informações sobre a magnitude e as razões para evasão escolar na população escolar rural.

Knowledge, attitudes, and practices about dengue among pupils from rural schools in an endemic area in Colombia / Conocimientos, actitudes y prácticas sobre dengue en estudiantes de escuelas rurales de un área endémica en Colombia

INTRODUCTION: Dengue is a public health problem in tropical and subtropical regions of the world. Studies on dengue in rural areas are scarce since the disease is considered mainly urban. OBJECTIVE: To determine the knowledge (K), attitudes (A) and practices (P) of dengue in an endemic area in Colombia. MATERIALS AND METHODS: We conducted a cross-sectional study with 515 pupils (7-16 years old) in 34 rural schools in Anapoima and La Mesa municipalities during 2011. Each KAP category was evaluated independently by a scoring system and then categorized into high, medium or low. RESULTS: Pupils recognized knowledge variables such as the symptoms (fever, bone pain), transmission route (mosquito bites), and mosquito breeding sites (uncovered water tanks, solid waste). Average scores on attitude were high in both municipalities indicating a well-developed perception of disease severity. Seeking treatment in medical centers and self-medication for fever management and the use of mosquito net and space-spraying of insecticides were the most frequently identified practices. DISCUSSION: This is the first KAP dengue study performed in a rural area in Colombia and as such it contributes to the understanding of dengue perceptions by the inhabitants of these areas. It showed a medium level of knowledge about dengue and a lower level of preventive practices in pupils from rural schools. It also showed that pupils considered space-spraying as crucial for vector control. The presence of the vector in rural areas of the country underlines the need to improve surveillance and education to more effectively control the vector and promote prevention methods including community participation.

Introducción. El dengue es un problema de salud pública en las regiones tropicales y subtropicales del mundo. Los estudios sobre la enfermedad en áreas rurales son escasos debido a que se presenta principalmente en los núcleos urbanos. Objetivo. Determinar los conocimientos, las actitudes y las prácticas sobre el dengue en un área rural endémica en Colombia. Materiales y métodos. Se hizo un estudio transversal con 515 estudiantes, entre los 7 y los 16 años de edad en 34 escuelas rurales de los municipios de Anapoima y La Mesa en el 2011. Cada categoría se evaluó por separado con un puntaje clasificado como alto, medio o bajo. Resultados. Los estudiantes reconocieron los síntomas (fiebre, dolor de huesos), la ruta de transmisión (picadura de mosquitos) y los criaderos (depósitos de agua destapados, residuos sólidos). El promedio de los puntajes de actitudes fue alto en ambos municipios, lo que indica que percibían la gravedad del dengue. Las prácticas más frecuentes de tratamiento de la fiebre fueron la consulta médica y la automedicación, en tanto que los métodos de control más frecuentes fueron el uso de mosquiteros y el rociamiento con insecticidas. Discusión. Este es el primer estudio de conocimientos, actitudes y prácticas sobre el dengue en un área rural de Colombia. Los resultados contribuyen a entender las percepciones de la enfermedad en sus habitantes y evidenciaron niveles medios de conocimiento y puntuaciones bajas en cuanto a las prácticas entre los estudiantes de las escuelas rurales. Los estudiantes consideraron que la fumigación es importante para el control del vector. La presencia del mosquito en áreas rurales del país resalta la necesidad de mejorar la vigilancia y la educación para lograr un control efectivo del vector y promover métodos de prevención que incluyan la participación comunitaria.

Knowledge, attitudes and practices about dengue among pupils from rural schools in Colombia / Conocimientos, actitudes y prácticas sobre dengue en estudiantes de escuelas rurales en Colombia

Abstract Introduction: Dengue is a public health problem in tropical and subtropical regions of the world. Studies on dengue in rural areas are scarce since the disease is considered mainly urban. Objective: To determine the knowledge (K), attitudes (A) and practices (P) of dengue in an endemic area in Colombia. Materials and methods: We conducted a cross-sectional study with 515 pupils (7-16 years old) in 34 rural schools in Anapoima and La Mesa municipalities during 2011. Each KAP category was evaluated independently by a scoring system and then categorized into high, medium or low. Results: Pupils recognized knowledge variables such as the symptoms (fever, bone pain), transmission route (mosquito bites), and mosquito breeding sites (uncovered wáter tanks, solid waste). Average scores on attitude were high in both municipalities indicating a well-developed perception of disease severity. Seeking treatment in medical centers and self-medication for fever management and the use of mosquito net and space-spraying of insecticides were the most frequently identified practices. Discussion: This is the first KAP dengue study performed in a rural area in Colombia and as such it contributes to the understanding of dengue perceptions by the inhabitants of these areas. It showed a medium level of knowledge about dengue and a lower level of preventive practices in pupils from rural schools. It also showed that pupils considered space-spraying as crucial for vector control. The presence of the vector in rural areas of the country underlines the need to improve surveillance and education to more effectively control the vector and promote prevention methods including community participation.

Resumen Introducción. El dengue es un problema de salud pública en las regiones tropicales y subtropicales del mundo. Los estudios sobre la enfermedad en áreas rurales son escasos debido a que se presenta principalmente en los núcleos urbanos. Objetivo. Determinar los conocimientos, las actitudes y las prácticas sobre el dengue en un área rural endémica en Colombia. Materiales y métodos. Se hizo un estudio transversal con 515 estudiantes, entre los 7 y los 16 años de edad en 34 escuelas rurales de los municipios de Anapoima y La Mesa en el 2011. Cada categoría se evaluó por separado con un puntaje clasificado como alto, medio o bajo. Resultados. Los estudiantes reconocieron los síntomas (fiebre, dolor de huesos), la ruta de transmisión (picadura de mosquitos) y los criaderos (depósitos de agua destapados, residuos sólidos). El promedio de los puntajes de actitudes fue alto en ambos municipios, lo que indica que percibían la gravedad del dengue. Las prácticas más frecuentes de tratamiento de la fiebre fueron la consulta médica y la automedicación, en tanto que los métodos de control más frecuentes fueron el uso de mosquiteros y el rociamiento con insecticidas. Discusión. Este es el primer estudio de conocimientos, actitudes y prácticas sobre el dengue en un área rural de Colombia. Los resultados contribuyen a entender las percepciones de la enfermedad en sus habitantes y evidenciaron niveles medios de conocimiento y puntuaciones bajas en cuanto a las prácticas entre los estudiantes de las escuelas rurales. Los estudiantes consideraron que la fumigación es importante para el control del vector. La presencia del mosquito en áreas rurales del país resalta la necesidad de mejorar la vigilancia y la educación para lograr un control efectivo del vector y promover métodos de prevención que incluyan la participación comunitaria.

Dengue-like illness surveillance: a two-year longitudinal survey in suburban and rural communities in the Lao People's Democratic Republic and in Thailand.

OBJECTIVE: This study aimed to determine the incidences of dengue-like illness (DLI), dengue virus (DENV) infection, and serotypes and to identify socio-demographical and entomological risk factors of DLI in selected suburban and rural communities in the Lao People's Democratic Republic and in Thailand. METHODS: A two-year longitudinal study was conducted in four villages during the inter-epidemic period between 2011 and 2013. Entomological surveys, semi-structured interviews of household heads and observations were conducted. Occurrences of DLI were recorded weekly using the World Health Organization's dengue definition along with blood samples; results were compared with national surveillance dengue data. Risk factors of DLI were assessed using logistic regression. RESULTS: Among the 2007 people in the study, 83 DLI cases were reported: 69 in suburban Lao People's Democratic Republic, 11 in rural Thailand, three in rural Lao People's Democratic Republic and none in suburban Thailand. Four were confirmed DENV: two from suburban Lao People's Democratic Republic (both DENV-1) and two from rural Thailand (both DENV-2). Although the number of detected DLIs during the study period was low, DLI incidence was higher in the study compared to the dengue surveillance data in both countries. DLI in suburban Lao People's Democratic Republic was associated with age and occupation, but not with the number of pupae per person. DISCUSSION: This study highlights the importance of continuous clinical and vector surveillance for dengue to improve early detection of dengue and other mosquito-borne diseases in the region.

Efficiency of chlorine and UV in the inactivation of Cryptosporidium and Giardia in wastewater.

Wastewater from different sources is contaminated by protozoan parasites including Cryptosporidium and Giardia. Many protozoan parasites are becoming resistant to chemical treatment. The challenge of finding alternatives is presented to researchers by exploring other methods of eliminating protozoan parasites from wastewater. The aim of this study was to assess the speciation and the viability of Cryptosporidium and Giardia in environmental samples with the specific objective of evaluating if effluent chlorination and UV affect the viability. Different doses of chlorine with different exposure times were experimented with both distilled water and waste water spiked with (oo)cysts derived from environmental samples. UV irradiation at different doses was also experimented using the same spiked samples. Two methods of quantification and detection, namely, microscopy and flow cytometry, were used in the experiment. Two vital dyes, Syto-9+PI and DAPI+PI, were the used for staining the collected wastewater samples. It was found that the (oo)cysts responded to chlorination and UV treatments with Giardia responding better than Cryptosporidium. Giardia responded very well to UV irradiations with almost 0 percent remaining viable after a low dose of UV. Cryptosporidium was found to be resistant to chlorination even at high doses but responded well to high UV doses. DAPI+PI dye gave a lower mean percentage viability values than Syto-9+PI. Flow cytometry gave higher mean percentage than microscopy from the results. It is concluded that UV is a promising alternative to Chlorine in removing Cryptosporidium and Giardia from waste water. Appropriate treatment method for wastewater is necessary to minimize water resources pollution when wastewater is released into water systems.

Concentration of soil-transmitted helminth eggs in sludge from South Africa and Senegal: A probabilistic estimation of infection risks associated with agricultural application.

The use of sludge in agriculture has been encouraged as a means of increasing soil nutrient content and improving the water holding capacity. On the negative side, major public health concerns with sludge application prevail, mainly due to the high concentration of pathogenic microorganisms. Soil-transmitted helminths (STHs) are of major health concern in this regard, especially in endemic regions, mainly due to the high environmental resistant of the eggs combined with a low infectious dose. In this study the concentration of STH eggs in two months dried sludge from Durban, South Africa and Dakar, Senegal was determined and compared. Sampling was carried out from January to October 2016 and in September 2016 for Dakar. Ascaris spp, hookworm, Trichuris spp, Taenia spp and Toxocara spp were the commonly recorded STH eggs. STH egg concentrations were higher in Dakar than in Durban, with viable STH egg concentrations exceeding both local and international guidelines. Due to the high concentration of viable STH eggs, risks of Ascaris spp infection was very high for farmers applying this sludge on their farms in both Durban (7.9 × 10-1 (±1.7 × 10-2)) and Dakar (9.9 × 10-1 (±1.3 × 10-5)). Consumption of lettuce grown on sludge amended soil will result in probable infections but harvest after 30 days between sludge application and harvest in Durban gave median probability infection risks with a risk level similar to the WHO tolerable risk value (10-4). This time period need to be prolonged to harvest in Dakar to 40 days to reduce the risks of infection to the tolerable risks values. Further treatment of the sludge either through composting or drying for longer periods of time is thus recommended from a public health perspective.

Soil-transmitted helminth infections associated with wastewater and sludge reuse: a review of current evidence.

OBJECTIVE: To review current evidence on infections related to the concentration of soil-transmitted helminth (STH) eggs in wastewater, sludge and vegetables irrigated with wastewater or grown on sludge-amended soils. METHOD: Search of Web of Science, Science Direct, PubMed and Google Scholar databases for publications reporting on STH egg concentration in wastewater, sludge and vegetables and for epidemiological studies on wastewater/sludge reuse and STH infections. RESULTS: STH egg concentrations were variable but high in wastewater and sludge especially in developing countries. They ranged from 6 to 16 000 eggs/L in wastewater and from 0 to 23 000 eggs/g in sludge and far exceed limits set in the WHO guideline for wastewater/sludge reuse. Numbers of STH eggs on vegetables ranged from 0 to 100 eggs/g. The concentration of STH eggs in wastewater, sludge and vegetables therefore relates to risks of infection through different exposure routes. CONCLUSION: Epidemiological evidence reveals an increased prevalence of STH infections associated with direct exposure to wastewater or sludge (farmers) and consumption of vegetables grown on soil treated with it. This calls for increased efforts to reduce the adverse health impact of wastewater and sludge reuse in line with the WHO multi-barrier approach.

Methods for the detection of Cryptosporidium and Giardia: From microscopy to nucleic acid based tools in clinical and environmental regimes.

The detection and characterization of genotypes and sub genotypes of Cryptosporidium and Giardia is essential for their enumeration, surveillance, prevention, and control. Different diagnostic methods are available for the analysis of Cryptosporidium and Giardia including conventional phenotypic tools that face major limitations in the specific diagnosis of these protozoan parasites. The substantial advancement in the development of genetic signature based molecular tools for the quantification, diagnosis and genetic variation analysis has increased the understanding of the epidemiology and preventive measures of related infections. The conventional methods such as microscopy, antibody and enzyme based approaches, offer better detection results when combined with advanced molecular methods. Gene based approaches increase the precision of identification, for example, many signatures detected in environmental matrices represent species/genotype that are not infectious to humans. This review summarizes the available methods and the advantages and limitations of advance detection techniques like nucleic acid-based approaches for the detection of viable oocysts and cysts of Cryptosporidium and Giardia along with the conventional and widely accepted detection techniques like microscopy, antibody and enzyme based ones. This technical article also encourages the wide application of molecular methods in genetic characterization of distinct species of Cryptosporidium and Giardia, to adopt necessary preventive measures with reliable identification and mapping the source of contamination.

Removal of helminth eggs by centralized and decentralized wastewater treatment plants in South Africa and Lesotho: health implications for direct and indirect exposure to the effluents.

Wastewater may contain contaminants harmful to human health; hence, there is the need for treatment before discharge. Centralized wastewater treatment systems are the favored treatment options globally, but these are not necessarily superior in reduction of pathogens as compared to decentralized wastewater treatment systems (collectively called DEWATS). This study was therefore undertaken to assess the soil-transmitted helminth (STH) and Taenia sp. egg reduction efficiency of selected anaerobic baffled reactors and planted gravel filters compared to centralized wastewater treatment plants in South Africa and Lesotho. The risk of ascariasis with exposure to effluents from the centralized wastewater treatment plants was also assessed using the quantitative microbial risk assessment (QMRA) approach. Eggs of Ascaris spp., hookworm, Trichuris spp., Taenia spp., and Toxocara spp. were commonly detected in the untreated wastewater. The DEWATS plants removed between 95 and 100% of the STH and Taenia sp. eggs, with centralized plants removing between 67 and 100%. Helminth egg concentrations in the final effluents from the centralized wastewater treatment plants were consistently higher than those in the WHO recommended guideline (≤ 1 helminth egg/L) for agricultural use resulting in higher risk of ascariasis. Therefore, in conclusion, DEWATS plants may be more efficient in reducing the concentration of helminth eggs in wastewater, resulting in lower risks of STH infections upon exposure.